Method for enantioselectively opening oxetan-2-ones
A method for preparing substantially enantiopure 3-hydroxy carboxylic acids or esters of the general formula (III) by reacting racemic oxetan-2-ones of the general formula (I) with compounds R3-OH of the general formula (II) in the presence of a lipase from Candida antartica or Burkholderia plantarii , and separating the resulting products of the formula (III) and (IV) from one another where the radicals have the following meaning: R 1 , R 2 , R 3 independently of one another H; C 1 -C 10 -substituted or unsubstituted alkyl, substituted or unsubstituted aryl or hetaryl, where R 1 and R 2 may not simultaneously have the same meaning.
1. A method for preparing substantially enantiopure 3-hydroxy carboxylic acids or esters of the formula (III) and/or substantially enantiopure oxetan-2-ones of the formula (IV) comprising the steps of
(1) reacting racemic oxetan-2-ones of the general formula (I) with compounds of the general formula (II) in the presence of a lipase from Candida antarctica or Burkholderia plantarii , and
(2) separating the resulting products of formulae (III) and (IV) from one another
wherein R 1 , R 2 , and R 3 are, independently of one another, H, C 1 to C 10 substituted or unsubstituted alkyl, or substituted or unsubstituted aryl or heteroaryl, with the proviso that R 1 cannot equal R 2 .
2. The method according to claim 1 , wherein R 1 is H and R 2 is selected from the group consisting of n-butyl, methyl, ethyl, isopropyl, and phenyl.
3. The method according to claim 1 , wherein the reaction of step (1) is carried out in the presence of methyl tert-butyl ether.
4. The method according to claim 1 , wherein said lipase is carrier-bound.
5. The method according to claim 1 , wherein the reaction of step (1) is carried out continuously.
6. The method according to claim 1 , wherein the separation of step (2) is accomplished by distillation, extraction or a combination thereof.
7. The method according to claim 2 , wherein the reaction of step (1) is carried out in the presence of methyl tert-butyl ether.
8. The method according to claim 7 , wherein said lipase is carrier-bound.
9. The method according to claim 8 , wherein the reaction of step (1) is carried out continuously.
10. The method according to claim 9 , wherein the separation of step (2) is accomplished by distillation, extraction or a combination thereof.